[Backport 1.8.latest] Update dbt-adapters ref to monorepo subdirectory (

#1304)

* update dbt-adapters ref to monorepo subdirectory (#1297)

* remove merge conflict artifact

dev-requirements.txt

@@ -1,7 +1,7 @@
 # install latest changes in dbt-core
 # TODO: how to automate switching from develop to version branches?
 git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-core&subdirectory=core
-git+https://github.com/dbt-labs/dbt-adapters.git
+git+https://github.com/dbt-labs/dbt-adapters.git#subdirectory=dbt-adapters
 git+https://github.com/dbt-labs/dbt-adapters.git#subdirectory=dbt-tests-adapter
 
 # if version 1.x or greater -> pin to major version